One or more therapeutic agents may be applied to or together with an orthopedic implant to aid in fighting infection, for example, at a surgical site. Such agents are generally applied to or somehow in connection with an implant prior to its implantation in or on the body of a patient, but may be applied after implantation.
Prior to implantation of an implant, a therapeutic agent such as an antibiotic may be spray coated onto the outside surface of the implant. The amount of antibiotic, the location in or on the implant that the antibiotic is applied to, and the velocity of the antibiotic spray, for example, is generally determined prior to the implant being sprayed with the antibiotic. By altering these factors, the therapeutic effect of the agent may also be altered. The implant may instead be dipped in a bath of the antibiotic, for example, such that the antibiotic may be quickly and easily applied to the inner and outer surfaces of the implant. One or more therapeutic agents may be applied to the implant in layers, perhaps via the aforementioned spray or bath, or may instead be combined to form a solution or compound that may be applied to the implant.
After implantation of an implant, a therapeutic agent such as an antibiotic may be supplied to the surgical site or onto the implant itself through a fastener, such as a bone screw. In such a case, the fastener may be sprayed or bathed, for example, with the antibiotic prior to being used to secure the implant at a specific location in or on the body of the patient.
Some therapeutic agents whether applied directly to an implant or introduced to the surgical site via a fastener, are time released, such that a predetermined amount of the therapeutic agent may provided to the surgical site at generally specific time intervals. In such a case, the therapeutic agent may be applied to the implant prior to its implantation in or on the body of the patient, and then may be released to provide a therapeutic effect to the surgical site after it has been implanted 12 hours, for example. A portion of the therapeutic agent applied to the implant may be released at that 12 hour time period, while one or more portions of the therapeutic agent may then be released at one or more later times.
Implants may alternatively be provided with internal reservoirs housing one or more therapeutic agents. The agents inside the reservoirs are generally released to the surgical site after the implant is implanted in or on the body of the patient. The therapeutic agent may seep out of the reservoir, for example, through a small opening in the reservoir regulating the release of the agent.